[Snake]

Riposte triggers while the enemy is knocked down, is it intentional?

[Autumn]

It always had done this as far as I'm concerned, so it's not really a bug.

[Nanovelich]

Accepting attacks and then returning them is a basic form of swordplay. When you are attacked in melee range, there is a chance that you will perform an automatic attack on your attacker. This skill will not trigger for attacks made directly behind you.

Considering the description doesn't mention knockdown canceling it as other skills of this nature do, I would assume it's intentional.

[Snake]

Aight, thanks.